thompson



(No Model.)

A. T. THOMPSON.

A ELECTRIC LAMP SUPPORT.

N0.'407,9 73. Patented July 30, 1889.

l I enZargeaZ l x I an Zine LX.

wif/www. jfzw/zzm #gw f4/56H1 27Min/Jawa.

N. versus, Pnawmmgmmr, wuhingmm D. c;

UNITED STATES PATENT OrrICEe b ALBERT T. THOMPSON, OE BOSTON, MASSACHUSETTS, ASSIGNOR TO ALBERTv T. THOMPSON da OO., OF SAME PLACE.

ELECTRIC-LAMP SUPPORT.

SPECIFICATION forming part of Letters Patent No. 407,973, dated July 30, 1889. Application iiled November l2, 1888. Serial No. 290,554. (No model.)

To all whom it may concern.'

Beitknown thatl, ALBERT T. THOMPSON, a

citizen of the United States, residing at Bos-- ton, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Electric-Lamp Supports; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled 1o in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification,

I5 This invention relates to mechanism by .which electric lamps, particularly arc lamps, so called, can be adjusted in position in both vertical and horizontal planes.

The device embodying' my invention is inzo tended to be used with apparatus where rays of light are to be transmitted through a lens upon a screen. In such apparatus it becomes necessary to maintain the central point of the source of light (the electric arc in the present example) centrally of the lens, in order to properly light the entire screen-surface, and thus produce the desired effect.

The drawings represent in Figure l a front viewin elevation of an apparatus embodying 3o my invention. Eig. 2 is a similar side view. Fig. 3 is a horizontal section on line x Fig. l; Fig. 4, a vertical section on y y in Fig. Fig. 5 shows the proper position of carbons and lens when not vertical.

3 5 In said drawings, A represents a support or frame composed of two similar upright posts a a., each secured upon a base B and united by horizontal cross-bars ZJ hat top and hottom. Centrally between the posts is hung an 4o electric-lamp apparatus O of the class termed arc lamps. This apparatus is of the usual construction, and is to be supported by acentral rod c.' The end of the latter is provided with a hook or eye, to which is fastened one end of a rope or cord extending about a pulley Cl, beneath the upper bar b, and thence downwardvhere it is coiled about a drum D. The latter is horizontally located between the posts a a, some distance below the light, and is furnished at one extremity with a ratchetwheel s, the latter actuated by a hand-wheel or other equivalent de vice. Said ratchetwheel s engages with a dog e, loosely secured to one of the posts and adjacent thereto. By this means the position of the electric lamp may be adjusted in horizontal planes and raised or lowered to any desired extentto suit the position of the lens in the apparatus with which it is to be employed.

In apparatus which are now generally used 6o for throwing or displaying l photographic views, depicted on transparent plates upon a screen for the purpose of illustrating lectures or for advertising purposes, a double-convex lens is usually employed, and in lieu of having an oxyhydrogcn or calcium light I iind an electric lamp, preferably an arc light, may be substituted therefor and with better results. In the use of such lights I iind, however, certain objections, which it is the object 7o of this invention to overcome-that is, when the position of the lens is changed, or when its longitudinal axis is shifted more or less from a vertical plane to cause the rays therethrough to be thrown upward or downward to suit the position of the screen, the electriclamp apparatus does not move in unison therewith. I further iind by experiment, in order to produce the best effect and light the screen throughout, that the longitudinal axis 8o of the lens should be parallel with the pencilcarbons of the electric-arc lamp. Hence to be able to adjust the position of said carbons in vertical planes, or to change their Obliquity and thereby enable them to be always placed in parallelism with the longitudinal axis of the lens for any slight shift or change in the position of the latter, I have, in connection with the mechanism before described, colnbined the following instrumentalities: 9o

As will be seen upon reference to the drawings, the electric-light apparatus is furnished with two vertical connecting-rods f f, which are adapted to slide within twin rocking guide-bars E E, fastened upon the inner faces of the posts a a. Said guides are pivotally secured by screws t t to the posts, and are actuated or changed to any desired position from a vertical plane to any semi-vertical or oblique plane, as may be desired, by means of twiuroo actuating screw-rods h h, mounted in brackets z' t', also upon said posts. Said rods engage sleeve-nuts 7a 7c, pivoted in the guides.

The screw-rods, although capable of rotation in their brackets, are prevented from endwise motion therein by pins m m; hence upon rotation of the said rods 7L h, their cooperating nuts k k are compelled to travel in a direction corresponding to the rotation of the screw-rods, and the guides are accordin gly tilted or inclined from the vertical, and with them the light apparatus. In this manner horizontal adjustment of the arc is effected by means of the drum with its ratchet and dog, the lamp apparatus moving longitudinally in the guides for any 'movement' of the drum, while by means of lthe screw-rods and sleeve-nuts within the guides the position of the pencil-carbons may be inclined from the vertical. The pencils are thus easily shifted to compensate for any change in the position or angle of the lens, and the rays can be directed at all times centrally of the lens in lieu of being thrown at one time upon the upper and again upon the lower part, incident to the varying position of the screen with respect to the lens, or vice versa.

What I desire to claim isl. A support for'electric-arc lamps, consistving of two vertical standards, twin rocking guides'pivoted to said standards, and a lampframe having a sliding connection with said guides and vertically adjustable therein,

whereby the lamp and its pencil-earb'ons can be maintained in a vertical plane or inclined therefrom, substantially as set forth.

2. The combination of a supporting-frame, and an electric lamp and lamp-frame pendent therein, with a drum, pawl, ratchet, and chain for raising and lowering said lamp and lamp -frame to any required position, and rocking guides pivoted to said frame and arranged for sliding connection with said lampframe, whereby said lamp and its pencil-carbons can be maintained in an inclined or vertical position, substantially as set forth.

3. In a support for electric lamps, the supporting-frame A, in combination with a lamp and lamp-frame hung` therein, guides pivoted to said supporting-frame and `having sliding` connection with said lamp-frame, the drum,

-pawl, ratchet, and chain, whereby said lampframe is raised and lowered and held in any desired position of adjustment, the sleevenuts 7c 7s within said guides, and the actuating screw-rods 7L h, the said guides allowing said lamp and its pencil-carbons to occupy either a vertical or an inclined position, substantially as set forth.

In testimony whereof I aiiiX my signature in presence of two witnesses.

ALBERT T. THOMPSON.

Vitnesses:

H. E. LODGE, FRANCIS C. SrANwooD. 

